Internal polls can play with numbers

Imagine a U.S. Senate with Charlie Melancon, Jack Conway and Elaine Marshall.

If internal Democratic polls released for public consumption during the 2010 cycle were to be believed, it seemed entirely plausible. The numbers commissioned by the campaigns and published in the closing months showed them ahead or within striking distance of victory.

Story Continued Below

All three lost badly. But that isn’t stopping campaigns from pushing a new batch of internal data to the media this year. The goal, by all appearances, is to frame the latest round of second-tier Senate races as much more competitive than conventional wisdom suggests they actually are.

The release of the internal data is becoming an increasingly common campaign tactic that’s here to stay — regardless that they’re hardly predictive. And both sides play the game, of course.

Republican candidates such as Sen. Scott Brown of Massachusetts and Sen. Dean Heller of Nevada have also turned to internals this cycle to project strength at early points in their races. But those poll releases weren’t as potent because there’s widespread agreement on the competitiveness of their contests.

The practice has been more pronounced among Senate Democratic contenders this cycle and in 2010 as they try to hang on to their four-seat majority by making Republicans sweat in GOP-friendly states.

“The major reason is to affect media coverage and fundraising. People like to be with a winner and if you have a poll that says you’re going to win, you can fire up your supporters and demoralize your opponents,” veteran GOP pollster John McLaughlin said.

Yet horse-race numbers can still have an outsize impact on how voters perceive a particular contest.

Take the North Dakota Senate race in which the first independent poll of the general election dropped last week showing GOP Rep. Rick Berg with a 7-point lead over Democrat Heidi Heitkamp.

Democrats, whose chances of retaining the Senate are primarily contingent on preventing four pickups by the GOP, swiftly moved to discredit the Essman/Research data compiled in early May and commissioned by the Fargo Forum.

Aside from their gripe that the firm limited its sample to likely primary voters, Democrats had another weapon to push back with: an internal poll conducted on behalf of the state party.

In late April, DFM Research — a Democratic pollster based in St. Paul, Minn. — produced a survey showing Heitkamp holding a 5-point advantage.

A double-digit swing in just 2½ weeks? Without a major market-moving event to point to, both sides conceded that was unlikely.

DFM was the same pollster that produced a poll in August of 2008 showing Barack Obama leading John McCain by 3 percentage points in North Dakota. (McCain defeated Obama in November getting 53 percent of the vote to Obama’s 45.)